Effects of Functional Rehabilitation on Muscle Strength, Dynamic Balance and Functional Performance 1 Year after Anterior Cruciate Ligament Reconstruction: A Randomised Controlled Trial

BACKGROUND: Return to sport (RTS) success rates remain suboptimal for high sports demand individuals (HSDs) following anterior cruciate ligament reconstruction (ACLR). Traditional rehabilitation model (TRM) primarily focuses on strength recovery and range of motion but demonstrates deficiencies in neuromuscular control and sport-specific conditioning. AIMS: This study aimed to compare the effects of functional rehabilitation model (FRM) versus Traditional rehabilitation model (TRM) on post-operative functional recovery and RTS outcomes in HSDs. METHODS: A prospective single-blind randomised controlled trial was conducted including 64 HSDs who underwent ACLR (exercise ≥3 times per week, Tegner score >5), randomly allocated to the FRM group ( n = 32) and TRM group ( n = 32). The FRM group received a performance-based progressive 24-week rehabilitation protocol incorporating multimodal sensory training, closed-chain exercises, unstable surface proprioceptive training and sport-specific skill integration. The TRM group received a standard time-oriented 24-week rehabilitation protocol. The primary outcomes included 48-week RTS rate and functional recovery trajectory. The secondary outcomes included isokinetic strength, single-leg hop tests, modified star excursion balance test, proprioception and patient-reported outcomes (International Knee Documentation Committee [IKDC], Lysholm and Anterior Cruciate Ligament-Return to Sport after Injury [ACL-RSI]). Assessment time points included pre-operative baseline, 24 weeks and 48 weeks postoperatively. Repeated measures analysis of variance was used to evaluate longitudinal changes. RESULTS: Fifty-seven patients completed follow-up (retention rate: 89.1%). The FRM group demonstrated significantly higher 48-week successful RTS rate compared to the TRM group (89.3% vs. 62.1%, P = 0.038), with relative risk 1.44 (95% confidence interval: 1.05-1.97) and number needed to treat 3.7. Repeated measures analysis revealed that the FRM group significantly outperformed the TRM group in quadriceps peak torque (48 weeks: 124.17 ± 7.25 vs. 98.42 ± 8.73 Nm, P < 0.001) and limb symmetry index (89.15% ± 3.85% vs. 69.45% ± 5.15%, P < 0.001). In single-leg hop tests, the FRM group demonstrated superior performance in lateral hop time (5.54 ± 2.25 vs. 7.84 ± 3.37 s, P = 0.004) and box hop symmetry index (97.50% ± 29.60% vs. 76.20% ± 31.40%, P = 0.011). Proprioceptive testing showed that the FRM group had smaller position sense errors at 30° (2.83° ± 1.63° vs. 4.25° ± 1.85°, P = 0.002) and 45° knee flexion angles (6.37° ± 1.69° vs. 7.57° ± 1.73°, P = 0.008). Patient-reported outcomes demonstrated the FRM group superiority in IKDC (89.45 ± 9.72 vs. 83.45 ± 12.73, P = 0.028), Lysholm (88.71 ± 5.78 vs. 76.12 ± 12.38, P < 0.001) and ACL-RSI scores (79.52 ± 8.17 vs. 70.35 ± 10.24, P < 0.001). The FRM group exhibited sustained linear improvement patterns, while the TRM group showed a recovery plateau after 24 weeks. CONCLUSION: Compared to TRM, FRM significantly improved functional recovery trajectories and RTS outcomes in HSDs through enhanced neuromuscular control, improved dynamic performance and increased psychological readiness.